1. Field of Invention
The present invention is related to a method of forming a conductive via plug and particularly to a method of forming the conductive via plug by use of inkjet with etching and depositing proceeding simultaneously.
2. Related Art
For a long time, a deposition-lithography-etching operation has been the primary process for manufacturing of conventional printed circuit boards (PCBs), semiconductor devices, flat displays and integrated circuits (ICs). For the first used deposition process, chemical vapor deposition (CVD) or physical vapor deposition (PVD) such as evaporating or sputtering is used for generating a blanket deposition. Next, exposure and photoresist develop processes are undertaken for the deposited layer to cause a desired photoresist left pattern. Next, a wet etching or a dry etching is exercised on the left pattern to obtain a desired layer pattern.
This process concept has long been used in IC and flat panel display manufacturing, and often ten and more times of repeat of the deposition-lithography-etching must be repeated ten times or more for a finished production. The finished product has reliable physical and electrical characteristics, but the costs of manufacturing process and the corresponding equipment are high. In recent years, many printing methods have been developed, in an attempt to print desired layers by outputting patterning deposition. For instance, H. Gleskova et al. used electro-photographic printing carbon powder on the photoresist to supercede the conventional exposure. W. S. Wang et al. used an acoustic inkjet to print wax material, to take the place of the lithography. Evenly, C. M. Hong et al. printed golden, silver, copper particles, etc. by the inkjet method to produce a conductive drain/source of a thin film transistor (TFT). Further, S. B. Fuller et al. utilized nano particles to manufacture lines of an actuator.
However, the printing method has a poorer resolution or a non-uniform or unrefined line width. For both the TFT and PCB applications, reducing manufacturing process and its equipment can be the most significant issue and a simplified process issue is required. In the multilevel interconnect case in the TFT and PCB applications, the manufacturing process is yet much more complex than in the general line printing. In this case, a via hole between the different conductive layers needs to be connected and the printing for an isolator between the different conductive layers is more complex. In the current literature, the multilevel interconnect is described according to two methods. One is to print a polyketone resin with a thickness of 40 μm at a first and a second conductive layer to isolate the two conductive layers, where a silver particles solution is used as the conductive layer. The other is provided by Takeo Kawase et al., where a 500 nm PVP (poly-vinyl pheonl) is used to totally cover a first conductive layer, then a soluble PVP is printed by the inject method to etch out a via, and then a second conductive layer is printed. The first and second conductive layers are made of organic polymers which have a much greater resistivity than silver particles. At the same time, a via hole between the two conductive layers has a resistivity of 0.5 MΩ order.